code: def f(params):
      return f1(params) + f2(params) + f3(params)
  
file_path: lmfit-py/examples/example_brute.py
imports: import copy
  from matplotlib.colors import LogNorm
  import matplotlib.pyplot
  import numpy
  from lmfit import Minimizer, create_params, fit_report
label_desc: Use image node_id 4 for calling a global function with example usage: f(params) and returns: unknown